U.S. patent number 9,294,135 [Application Number 13/609,638] was granted by the patent office on 2016-03-22 for digital radio frequency (rf) receiver.
This patent grant is currently assigned to ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. The grantee listed for this patent is Ik Soo Eo, Seon-Ho Han, Sang-Kyun Kim, Mun Yang Park, Hyun Kyu Yu. Invention is credited to Ik Soo Eo, Seon-Ho Han, Sang-Kyun Kim, Mun Yang Park, Hyun Kyu Yu.
United States Patent |
9,294,135 |
Eo , et al. |
March 22, 2016 |
Digital radio frequency (RF) receiver
Abstract
A digital RF receiver does not use a separate receiver according
to a mode and a band for multi-mode reception, MIMO reception, and
bandwidth extension reception, and changes only setting variables
in a single receiver structure so as to implement multi-mode
reception, MIMO reception, bandwidth extension reception, and/or
simultaneous multi-mode operation, such that complexity of the
receiver, development cost, and power consumption can be
reduced.
Inventors: |
Eo; Ik Soo (Daejeon,
KR), Kim; Sang-Kyun (Gyeongsangbuk-do, KR),
Park; Mun Yang (Daejeon, KR), Han; Seon-Ho
(Daejeon, KR), Yu; Hyun Kyu (Daejeon, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Eo; Ik Soo
Kim; Sang-Kyun
Park; Mun Yang
Han; Seon-Ho
Yu; Hyun Kyu |
Daejeon
Gyeongsangbuk-do
Daejeon
Daejeon
Daejeon |
N/A
N/A
N/A
N/A
N/A |
KR
KR
KR
KR
KR |
|
|
Assignee: |
ELECTRONICS AND TELECOMMUNICATIONS
RESEARCH INSTITUTE (Daejeon, KR)
|
Family
ID: |
48610129 |
Appl.
No.: |
13/609,638 |
Filed: |
September 11, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130156141 A1 |
Jun 20, 2013 |
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Foreign Application Priority Data
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Dec 14, 2011 [KR] |
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10-2011-0134809 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B
1/0021 (20130101) |
Current International
Class: |
H04B
1/00 (20060101) |
Field of
Search: |
;375/316,324,346,350 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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100303311 |
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Jul 2001 |
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KR |
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1020010104054 |
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Nov 2001 |
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KR |
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100645924 |
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Nov 2006 |
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KR |
|
Other References
Rim Barrak et al., "Optimized Multistandard RF Subsampling Receiver
Architecture", IEEE Transactions on Wireless Communications, Jun.
2009, pp. 2901-2909, vol. 8, No. 6. cited by applicant.
|
Primary Examiner: Odom; Curtis
Attorney, Agent or Firm: Rabin & Berdo, P.C.
Claims
What is claimed is:
1. A digital RF receiver comprising: an antenna unit configured to
output a signal received at an antenna; a radio frequency (RF) unit
configured to convert the received signal into a digital reception
signal, and output the digital reception signal; and a digital
front end (DFE) unit configured to perform a decimation process for
the digital reception signal and remove an interference signal
component of a contiguous band, wherein variables of an input
sampling rate, a carrier frequency and a bandwidth are established
in the RF unit, and wherein variables of an output sampling rate, a
bandwidth, an inter frequency (IF), an integer decimation rate and
a rational decimation rate are established in the DFE unit.
2. The digital RF receiver of claim 1, wherein m digital RF
receivers (where m is a natural number), each of which includes the
antenna unit, the RF unit, and the DFE unit, are arranged in
parallel.
3. The digital RF receiver of claim 1, wherein the DFE unit
comprises a DC offset compensator configured to remove a DC
component from the received signal.
4. The digital RF receiver of claim 1, wherein the DFE unit
comprises an IQ mismatch compensator configured to remove image
components from the received signal.
5. A receiver set comprising: a plurality of digital RF receivers,
wherein each of the plurality of digital RF receivers includes: an
antenna unit configured to output a signal received at an antenna;
a radio frequency (RF) unit configured to convert the received
signal into a digital reception signal, and output the digital
reception signal; and a digital front end (DFE) unit configured to
perform a decimation process for the digital reception signal and
remove an interference signal component of a contiguous band,
wherein variables of an input sampling rate, a carrier frequency
and a bandwidth are established in the RF unit, wherein variables
of an output sampling rate, a bandwidth, an inter frequency (IF),
an integer decimation rate and a rational decimation rate are
established in the DFE unit.
6. The receiver set of claim 5, wherein m digital RF receivers
(where m is a natural number), each of which includes the antenna
unit, the RF unit, and the DFE unit, are arranged in parallel.
7. The receiver set of claim 6, wherein n receiver sets are
provided, each of the n receiver sets including the m digital RF
receivers in such a manner that m antenna units are available.
Description
CROSS-REFERENCE TO RELATED APPLICATION
The present application claims priority to Korean patent
application number 10-2011-0134809, filed on Dec. 14, 2011, which
is incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
The present invention relates to a digital radio frequency (RF)
receiver, and more particularly to a digital RF receiver which
changes only setting variables in a single receiver so that it can
implement multi-mode reception, Multiple Input Multiple Output
(MIMO) reception, and bandwidth extension reception.
RF transmission/reception signals for use in wireless communication
generally have different bands and different bandwidths according
to various communication standards, and may also have a plurality
of bands and a plurality of bandwidths in only one standard as
necessary.
In recent times, a new communication standard has been proposed to
increase a signal transfer rate, and the MIMO scheme and the
bandwidth extension technology capable of simultaneously
transmitting signals through a plurality of bands have also been
proposed, such that wireless communication RF
transmission/reception characteristics have become more diverse and
complex.
The related arts of the present invention are disclosed in Korean
Patent Laid-open Publication No. 2000-0066935 (entitled "CIRCUIT
AND DEVICE FOR RECEIVING RF SIGNALS IN MOBILE COMMUNICATION
TERMINAL"), Korean Patent Laid-open Publication No. 2001-0010375
(entitled "APPARATUS FOR TRANSMITTING/RECEIVING MULTI-BAND
HIGH-FREQUENCY SIGNAL OF MOBILE COMMUNICATION TERMINAL), and Korean
Patent Laid-open Publication No. 2001-0104054 (entitled "RF
RECEIVER FOR USE IN MOBILE COMMUNICATION TERMINAL).
However, according to a conventional RF receiver based on analog
technology, a new RF receiver is designed/manufactured whenever a
new standard is proposed and its associated band and bandwidth are
newly added, such that an RF reception function chip is developed
and applied to a terminal (hereinafter referred to as a user
equipment (UE)), resulting in an increase in time and cost needed
for such development.
In addition, when manufacturing a UE capable of supporting a
variety of communication standards, a plurality of chips capable of
restrictively supporting only individual standards are unavoidably
mounted to the UE, such that the size and power consumption of the
UE are unavoidably increased.
In addition, if a requested signal has a high transfer rate, the
conventional RF receiver simultaneously receives signals of
multiple antennas or simultaneously receives signals through
multiple bands, such that the RF receiver becomes more complicated
in construction.
SUMMARY OF THE INVENTION
Various embodiments of the present invention are directed to
providing a digital RF receiver that substantially obviates one or
more problems due to limitations or disadvantages of the related
art. Embodiments of the present invention provide a digital RF
receiver which does not use a separate receiver according to a mode
and a band for multi-mode reception, MIMO reception, and bandwidth
extension reception, and changes only setting variables in a single
receiver structure so as to implement multi-mode reception, MIMO
reception, bandwidth extension reception, and/or simultaneous
multi-mode operation, such that complexity of the receiver,
development cost, and power consumption can be reduced.
In accordance with one embodiment, a digital RF receiver includes:
an antenna unit for outputting a signal received at an antenna; a
radio frequency (RF) unit for converting the received signal into a
digital reception signal, and outputting the digital reception
signal; and a digital front end (DFE) unit for performing a
decimation process for the digital reception signal and removing an
interference signal component of a contiguous band.
M digital RF receivers (where m is a natural number), each of which
includes the antenna unit, the RF unit, and the digital front end
(DFE) unit, may be arranged in parallel.
Variables of a carrier frequency, a bandwidth, and an input
sampling rate are established in the RF unit, and variables of a
bandwidth, an integer decimation rate, a rational decimation rate,
and an output sampling rate may be established in the digital front
end (DFE) unit.
In accordance with other embodiment, a receiver set includes: a
plurality of digital RF receivers, wherein each of the plurality of
digital RF receivers includes: an antenna unit for outputting a
signal received at an antenna; a radio frequency (RF) unit for
converting the received signal into a digital reception signal, and
outputting the digital reception signal; and a digital front end
(DFE) unit for performing a decimation process for the digital
reception signal and removing an interference signal component of a
contiguous band.
M digital RF receivers (where m is a natural number), each of which
includes the antenna unit, the RF unit, and the digital front end
(DFE) unit, may be arranged in parallel.
N receiver sets may be provided, each of the n receiver sets
including the m digital RF receivers in such a manner that m
antenna units are available.
Variables of a carrier frequency, a bandwidth, and an input
sampling rate are established in the RF unit, and variables of a
bandwidth, an integer decimation rate, a rational decimation rate,
and an output sampling rate may be established in the digital front
end (DFE) unit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating a digital RF receiver
according to one embodiment of the present invention.
FIG. 2 is a block diagram illustrating a multi-mode digital RF
receiver according to another embodiment of the present
invention.
FIG. 3 is a block diagram illustrating a MIMO digital RF receiver
according to still another embodiment of the present invention.
FIG. 4 is a block diagram illustrating a bandwidth extension RF
receiver according to another embodiment of the present
invention.
FIG. 5 shows setting variables of the bandwidth extension digital
RF receiver shown in FIG. 4.
DESCRIPTION OF SPECIFIC EMBODIMENTS
Hereinafter, a digital RF receiver in accordance with the present
invention will be described in detail with reference to the
accompanying drawings. In the drawings, line thicknesses or sizes
of elements may be exaggerated for clarity and convenience. Also,
the following terms are defined considering function of the present
invention, and may be differently defined according to intention of
an operator or custom. Therefore, the terms should be defined based
on overall contents of the specification.
FIG. 1 is a block diagram illustrating a digital RF receiver
according to one embodiment of the present invention.
Referring to FIG. 1, the digital RF receiver 10 according to one
embodiment of the present invention includes am antenna, an
isolator 100, a transmission (Tx) block 110, a Low Noise Amplifier
(LNA) 120, a variable gain amplifier (VGA) 130, an
analog-to-digital converter (ADC) 140, a mixer 150, an integer
decimator 160, a DC offset compensator 170, an IQ mismatch
compensator 180, a rational decimator 190, and a channel selection
filter 200.
The digital RF receiver 10 receives a signal through an antenna,
inputs the received signal to the isolator for isolating a
transmission signal of the transmission block 110, and finally
inputs the isolated signal to the LNA 120, such that thermal noise
is reduced and the resultant signal is amplified.
The LNA 120 serves as a low noise amplifier that has a band
selection function capable of amplifying only a signal of the
selected band, such that it can selectively amplify a signal in
response to the magnitude of a bandwidth to be received. Therefore,
the output signal of the LNA 120 is a bandwidth-limited signal.
In order to perform mapping of the magnitude of a signal to the
entire output bits of the ADC 140 before applying the corresponding
signal to the ADC 140, the variable gain amplifier (VGA) 130
performs processing for adjusting a signal level.
The band-limitation RF signal to be received is converted into a
digital signal after passing through the ADC 140. The resultant
digital signal is input to the mixer 150 so as to remove an
intermediate frequency (IF) signal contained in the corresponding
signal. In-phase (I) and Quadrature-phase (Q) signals are generated
by processing of the mixer 150.
On the other hand, in order to convert a sampling signal of the ADC
140 into a sampling rate requested by a communication standard,
integer decimation and rational decimation are carried out in the
integer decimator 160 and the rational decimator 190, respectively.
The DC offset compensator 170 is used to remove DC components from
the received signal. The IQ mismatch compensator 180 is used to
remove image components, and the channel selection filter 200 is
used to remove interference signal component of a neighbor or
contiguous band.
The DC offset compensator 170 for performing a DC offset
cancellation function may also be located behind the mixer 150 so
as to increase the efficiency of digital signal processing. In
addition, a block for controlling a signal gain may be contained in
the integer decimator 160 and the channel selection filter 200,
respectively.
FIG. 2 is a block diagram illustrating a multi-mode digital RF
receiver according to another embodiment of the present
invention.
Referring to FIG. 2, the digital RF receiver 10 according to
another embodiment of the present invention may include an antenna
unit 105, an RF unit 115, and a digital front end (DFE) unit
155.
The antenna unit 105 may include an antenna, an isolator 100, and a
transmission block 110. The RF unit 115 may include a low noise
amplifier (LNA) 120, a variable gain amplifier (VGA) 130, and an
ADC 140.
The DFE unit 155 may include a mixer 150, an integer decimator 160,
a DC offset compensator 170, an IQ mismatch compensator 180, a
rational decimator 190, and a channel selection filter 200.
A multi-mode is used to support different wireless access
standards, and has different carrier frequencies, different
bandwidths, and different input sampling rates in terms of an RF
signal.
Referring to exemplary setting variables shown in FIG. 2, a carrier
frequency and a bandwidth in response to each mode shown in the
digital RF receiver of FIG. 1 are set to an LNA reception band and
bandwidth of the RF unit 115 and a sampling rate of the ADC 140
shown in FIG. 2, respectively. The DFE unit 155 establishes the
mixer, the integer and rational decimator filters, and the channel
selection filter according to a bandwidth and an output sampling
rate, such that it can also be used as a multi-mode digital RF
receiver.
In this case, information as to whether mixing is used, information
as to whether DC offset cancellation is used, and information as to
whether IQ signals are compensated can be established according to
an input signal.
That is, the RF receiver shown in FIG. 2 can operate as a
multi-mode digital RF receiver according to setting of various
variables shown in FIG. 2.
FIG. 3 is a block diagram illustrating a MIMO digital RF receiver
according to still another embodiment of the present invention.
The digital RF receiver shown in FIG. 3 is used upon receiving
signals from four different transmission antennas.
In the case of using the MIMO scheme, four receivers (Receiver1,
Receiver2, Receiver3, and Receiver4) are configured to receive the
same band signals and the same bandwidth signals.
Therefore, the RF receiver exemplarily shown in FIG. 2 may be
configured to be repeated four times in parallel. For reference,
RF1, DFE1, etc. shown in FIG. 3 are identical to those of FIG.
2.
In order to implement the MIMO scheme, the MIMO digital RF receiver
may selectively adjust variables (DFE_EN0, DFE_EN1, DFE_EN2, and
DFE_EN3) according to a transmission antenna structure.
For example, in the case of using only one transmission antenna,
one variable (DFE_EN0) may be set to 1, and each of the remaining
variables (DFE_EN1, DFE_EN2 and DFE_EN3) may be set to zero `0`. In
the case of using two transmission antennas, DFE_EN0 or DFE_EN1 may
be set to 1, and DFE_EN2 or DFE_EN3 may be set to zero `0`.
Assuming that all the four transmission antennas are used, DFE_EN0,
DFE_EN1, DFE_EN2 or DFE_EN3 may be set to `1`.
Setting variables are performed in the corresponding block, and the
same-value variable may be assigned to individual blocks (for
example, RF1 and RF2, or DFE1 and DFE2).
FIG. 4 is a block diagram illustrating a bandwidth extension RF
receiver according to another embodiment of the present invention.
FIG. 5 shows setting variables of the bandwidth extension digital
RF receiver shown in FIG. 4.
In more detail, FIG. 4 illustrates a bandwidth extension structure
for the MIMO digital RF receiver shown in FIG. 3. The bandwidth
extension RF receiver shown in FIG. 4 receives a carrier frequency
using a maximum of four reception antennas, and a maximum number of
received carrier frequencies may be set to 5.
Referring to FIG. 4, a first receiver set (Receiver Set1) receives
a first carrier frequency (Carrier Frequency 1), a second receiver
set (Receiver Set2) receives a second carrier frequency (Carrier
Frequency 2), a third receiver set (Receiver Set3) receives a third
carrier frequency (Carrier Frequency 3), a fourth receiver set
(Receiver Set4) receives a fourth carrier frequency (Carrier
Frequency 4), and a fifth receiver set (Receiver Set5) receives a
fifth carrier frequency (Carrier Frequency 5). Different carrier
frequencies and different bandwidths are assigned to individual
receiver sets for use in individual carrier frequencies.
Although 5 parallel receiver sets corresponding to individual
carrier frequencies are exemplarily shown in FIG. 4 in such a
manner that a maximum of 5 carrier frequencies can be
simultaneously received, the scope or spirit of the present
invention is not limited thereto because the above-mentioned
example is disclosed only for illustrative purposes, such that it
should be noted that the number of carrier frequencies capable of
being simultaneously received can be increased or reduced as
necessary.
In FIG. 4, according to individual bands to be used, different
antennas may be used, or the same antenna may also be commonly used
as necessary. However, a signal is isolated using different
antennas in a MIMO mode. The sampling frequency of the ADC may
utilize the same sampling frequency irrespective of a carrier
frequency. If the ADC is able to use another sampling frequency, an
intermediate frequency (IF) value is changed according to the
sampling frequency.
In this case, if a signal bandwidth of the RF output signal is
higher than that of the DFE unit, the RF output signal can be
divisionally processed by a plurality of DFE units.
Referring to FIG. 5, a variety of setting variables may be used for
the bandwidth extension digital RF receiver. In more detail, a
variety of setting variables depending upon a carrier frequency
used for bandwidth extension may be used, for example, a carrier
frequency, a bandwidth, an input sampling rate, an IF, an integer
decimation rate, a rational decimation rate, an output sampling
rate, Mixer_EN, etc. DFE_EN may be determined according to the
number of used antennas and the number of carrier frequencies.
However, VGA_EN, DC_EN, and IQ_EN may be determined irrespective of
the number of used antennas and the number of carrier
frequencies.
If the setting variables shown in FIG. 5 are adaptively applied to
the digital RF receiver shown in FIG. 4, the resultant digital RF
receiver capable of simultaneously transmitting various standards
may also be configured. That is, the setting variables shown in
FIG. 5 are not restrictively applied to only one standard, and may
also be simultaneously applied to a plurality of standards as
necessary.
As described above, the digital RF receiver according to the
embodiments of the present invention may operate as a multi-mode
digital RF receiver, a MIMO digital RF receiver and/or a bandwidth
extension digital RF receiver.
The RF reception signal is input to a low noise amplifier (LNA)
through an antenna and a duplexer for separating
transmission/reception signals. A noise component of the signal
applied to the LNA is prevented from being amplified, and the
magnitude of signal is increased. In addition, the LNA performs a
band-limiting filter function, such that it can sufficiently
convert a signal component of a band to be received by the ADC into
a digital signal. As a result, the LNA can previously remove
overlapped noise generated in a decimation process.
In order to allow an input signal of the ADC to have an optimum
magnitude, the signal is input to the ADC through the VGA. In
addition, a specific function for compensating a DC offset and an
IQ mismatch that are considered to be distortion components of the
resultant digital signal.
In order to satisfy the sampling rate requested by the standard,
integer decimation and rational decimation are processed in the
digital sampling rate, and the processed result is input to the
channel selection filter so as to filter a signal of a neighbor
band of a signal band.
Undesired interference signals are filtered (or removed) through
the integer decimation filter and the channel selection filter,
such that a gain control function for properly increasing the
magnitude of signal is needed. If a reception signal of the digital
signal output from the ADC has an intermediate frequency (IF)
according to the ADC sampling rate, a digital mixer for IF
cancellation is used to process the reception signal. Integer
decimation or rational decimation is performed according to the ADC
sampling rate.
In addition, band, bandwidth, input sampling rate, output sampling
rate, the use or disuse of a mixer, IQ mismatch correction, DC
offset correction, and a signal gain are established to perform the
digital RF function capable of supporting multiple modes
(multi-mode), multiple bands (multi-band), and multiple bandwidths
(multi-bandwidth).
The multi-mode supports a variety of wireless access standards, and
has different bands, different bandwidths, and different sampling
rates according to wireless access standards. The multi-band can
utilize one wireless access standard in a plurality of bands, such
that it can transmit a signal by assigning different bands to
individual service enterprisers.
Meanwhile, the MIMO scheme and the bandwidth extension scheme are
used to support a higher transfer rate within a limited contiguous
bandwidth. The MIMO scheme transmits different information pieces
through a plurality of transmission antennas, and isolates
different transmission signals using independent reception
antennas, such that it requires as many receivers as the number of
reception antennas. The bandwidth extension scheme transmits a user
signal using different bands, and simultaneously receives signals
of different bands using the receiver, resulting in an increase in
signal transfer rate.
As is apparent from the above description, the digital RF receiver
according to the embodiments of the present invention does not use
a separate receiver according to a mode and a band for multi-mode
reception, MIMO reception, and bandwidth extension reception, and
changes only setting variables in a single receiver structure so as
to implement multi-mode reception, MIMO reception, bandwidth
extension reception, and/or simultaneous multi-mode operation, such
that complexity of the receiver, development cost, and power
consumption can be reduced.
While the present invention has been described with respect to the
specific embodiments, it will be apparent to those skilled in the
art that various changes and modifications may be made without
departing from the spirit and scope of the invention as defined in
the following claims.
* * * * *